SAN FRANCISCO (AP) — A federal appeals court is considering a request by the self-proclaimed “toughest sheriff in America” to reverse a lower-court decision barring his deputies from detaining people based solely on the suspicion that they’re illegal immigrants.

A three-judge panel of the 9th Circuit Court of Appeals said it would rule later after hearing from lawyers representing Arizona lawman Joe Arpaio on Thursday.

The ACLU and other attorneys filed a federal lawsuit that alleges that Arpaio’s deputies pulled over Hispanics without probable cause, making the stops only to inquire about the immigration status of the people in the vehicles.

A federal judge in December barred Arpaio’s deputies who are enforcing Arizona’s immigrant smuggling law from detaining people based solely on the suspicion that they’re in the country illegally. In their appeal, Arpaio’s attorneys argued the ruling was deeply flawed and that the decision means that the sheriff’s office couldn’t enforce certain state laws, even though no judge has declared those statutes unconstitutional.

The San Francisco-based court will consider the narrow question of a preliminary injunction while a trial court in Phoenix is considering the merits of the entire lawsuit.

Both sides are awaiting the verdict of U.S. District Judge Murray Snow after a seven-day trial without a jury ended Aug. 2.

The Latino group claims Arpaio’s deputies pulled over some vehicles only to make immigration status checks during regular traffic patrols and the sheriff’s 20 special immigration patrols.

They also accuse the sheriff of ordering some of the patrols not based on reports of crime but rather on letters from Arizonans who complained about people with dark skin congregating in an area or speaking Spanish.

Arpaio has repeatedly denied the allegations, saying his deputies only stop people when they think a crime has been committed and that he wasn’t the person who picked the location of the immigration patrols.

Snow’s verdict could render the 9th Circuit’s decision unnecessary. Snow hasn’t indicated when he would rule.

The lawsuit marks the first case in which the sheriff’s office has been accused of systematically racially profiling Latinos, and will serve as a precursor for a similar yet broader civil rights lawsuit filed against Arpaio in May by the U.S. Department of Justice.

There has never been a finding by a court that Arpaio’s office has racially profiled Latinos, though a case that made such an allegation was settled last year for $200,000 without an admission of wrongdoing by the sheriff’s office.